1. Field of the Invention
The present invention relates to method and devices for introducing volatile fuel materials into an on-board fuel storage tank of an automotive vehicle in a safe and efficient manner. More particularly, the present invention pertains to methods and devices for introducing volatile fuels such as gasoline into an automotive vehicle in an environmentally safe manner which permits little or no discharge of hydrocarbon vapor or emissions into the surrounding atmosphere.
2. Brief Discussion of Relevant Art
The introduction of fuel to the on-board storage tank of an automotive vehicle presents various concerns regarding environmental and user safety. Specific among these are concerns regarding spillage of liquid fuel outside of the on-board storage tank before or after refueling procedures, exposure of the individual performing the refueling operation to liquid fuel and/or fuel vapors, and introduction of hydrocarbon emissions into the atmosphere during the refueling operation.
Heretofore, great attention was focused on elimination of unwanted spillage of liquid fuel before, during and after the refueling operation. To overcome such problems, modern fuel pumping devices are equipped with various sensors and automatic shut-off devices which can prevent addition of fuel to an over-full on-board storage tank. Additionally, fuel filler nozzles are equipped with manually operable triggers which serve to regulate and control the flow of the major portion of the fuel during the refueling operation.
Such devices fail to address the significant problem of gaseous hydrocarbon emissions produced and discharged during the refueling operation. In recent years, scientists and the general public have come to appreciate the detrimental impact uncontrolled hydrocarbon emissions have had and will continue to have on the environment. Hydrocarbon emissions may adversely impact the global environment as a whole; while, on a more personal level, long term exposure to elevated levels of hydrocarbons such as those generated during refueling operations may contribute to increased risks for health hazards such as cancer and the like.
Many devices have been proposed to reduce or limit the emission of hydrocarbons from sources such as those generated during refueling operations. These efforts have been fostered and mandated by the promulgation of new, tougher standards for hydrocarbon emissions levels. Among the devices and methods proposed for reducing hydrocarbon emissions during refueling operations are the addition of hydrocarbon capture canisters to the filler line of each automotive vehicle. Such devices would capture hydrocarbons in an adsorbtive media such as activated carbon as the gaseous hydrocarbons are emitted to prevent their escape into the surrounding atmosphere. Carbon canisters such as those proposed would be costly additions to new vehicles. Furthermore, in order to accomplish the sought after reduction in total refueling-related hydrocarbon emissions, carbon canisters would also have to be added to existing vehicles as costly retrofits.
Unfortunately, such adsorptive canisters will not provide maximum reduction or elimination of hydrocarbon emissions. Adsorptive canisters will still permit a portion of the gaseous hydrocarbons to escape. Additionally, as the adsorbtive canisters become saturated, replacement will be required at further expense to the operator of the vehicle. Because appropriate and timely replacement of spent or saturated adsorbtive canisters would be necessary to achieve maximum reduction in hydrocarbon emissions, a great deal of the success of such a program would rely on operator compliance. It has been the general experience that operators are adverse to large expenditures related to environmental compliance. Therefore significant amounts of capital will have to be dedicated to "over-designing" such devices to prevent premature failure and to eliminate excessive need to replace the adsorbtive canisters. Even so, it is foreseeable that governmental resources will be required to ensure that the vehicles remain in compliance with emission standards through new emission testing and the like.
As an interim measure, in an attempt to avoid the cost and confusion of such retrofits, various modifications have been proposed in the design of the fuel dispensing nozzle employed at most commercial gas stations. Examples of such modifications include the addition of a cowl over the fuel dispensing nozzle. In one embodiment, the cowl has an outer edge designed to engage the surface body panel surrounding the fuel filler opening to prevent the escape of fuel vapors during refueling. Such cowl designs would not prevent the escape of significant quantities of the hydrocarbon vapors which accumulate in the cowl and are released when the fuel filler nozzle is disengaged. A second embodiment of the cowl device is a deformable disc-like flange attached to the fuel filler nozzle which is adapted to roughly fit in the body opening located in most passenger vehicles in which the fuel filler nozzle is located. This device does not trap a significant portion of the emitted fuel vapors. Its major purpose is to divert fuel vapors from the operator of the fuel pump and prevent the inhalation of these materials.
None of the systems which have been proposed addresses the problem of spillage prior to or immediately after the refueling operation. This is particularly true with regard to spillage of residual fuel contained in the fuel filler nozzle.
Thus it is desirable to provide a device which would significantly reduce the level of gaseous hydrocarbons released during the refueling of a variety of automotive vehicles. It is also desirable to provide a refueling process and device which can essentially eliminate all hydrocarbon emissions generated as a result of refueling operations.
It is also desirable to provide a process and device which integrates the vehicle to be refueled and the refueling station into an essentially closed system, rather than treating the refueling operation as the temporary connection of two isolated elements. It is also desirable to provide a device which can eliminate gaseous hydrocarbon emissions in an economical manner which is easy to maintain, and easy to employ on and with existing automotive equipment and in existing refueling systems.